This patent relates to the use of a novel compound for reducing the buildup of creosote from the flues of combustion areas. The compound is comprised of hydrated aluminum silicate, calcium hydroxide and sodium bicarbonate.
Wood has been a primary source of residential heat throughout the history of the United States. Declines in solid fuel usage were noted with the advent of oil and gas furnaces. Additional declines were also noted with advances in residential heating, which included both passive and active solar heating, as well as heat pumps and geothermal heating, to name a few. Each advance in technology brought reductions in solid fuel heating until the realization that oil was not a renewable energy source and the oil embargo in the early seventies. As a result of these developments, the trend has been an increase in the use of residential heating.
Recent literature indicates that 59 percent of all new homes built in 1988 will include at least one fireplace--up from 54 percent the previous year. More than twelve million homes burned wood for the primary source of heat in 1986. In this same year, there were 113,000 reported residential fires as a result of burning wood. Based on 1983 data, this accounted for more than 26 percent of all residential fires. Based on a normal six-month heating season, it would be expected that one residential fire occurred every 1.9 minutes as a result of heating with wood. The total dollar loss due to these fires, in 1983, amounted to 745 million dollars, or about 4 million dollars per day during the heating season. Based on a national average of deaths resulting from residential fires, it would be expected that 789 deaths were related to heating with wood, or approximately one death every 4.32 hours, as well as one injury every 60 minutes.
The primary reason for residential fires, based on the C.R., dated September, 1985, is due to chimney fires. Fires result when there is an excess buildup of creosote within the chimney. According to this article, flammable creosote is deposited in the chimney while burning the wood, particularly the older airtight stoves that have been used for burning small, slow fires. When the temperature in the flue reaches 1500 degrees F., during start-up or reloading of some wood stoves, the creosote can ignite. If ignition takes place, sparks and/or flames can ignite the roof. As well, the flames can penetrate the walls of the chimney, igniting beams, rafters or other combustible materials, resulting in severe structural damage, personal injury or death.
One method for reducing the risk of fire, is the periodic cleaning of the chimney with wire brushes, chains, or rough fabric material by passing them down the chimney from the roof with a rope, cable, or rigid member. Any of the above-mentioned implements will break lose the flammable residue which, then, falls down the chimney flue to the clean-out area, at which point, it is removed by hand and discarded. This method is time consuming, messy and often requires the assistance of at least one other person to effectively complete the operation.
The second method for reducing flammable creosote is the addition of any of a number of commercially available chimney cleaning agents, which are placed directly into the fire, vaporized, and recondensed on the flue lining forming a thin chemical coating on the chimney wall, which helps reduce the formation of the creosote. These chemicals are seldom effective in fully preventing creosote buildup. Furthermore, this method does not solve the problem of eliminating existing creosote.
Another type of cleaning agent which is used quite widely has a low fire point, which ignites the creosote before excessive buildup occurs. Again, this method is not fully effective, and requires its use in the presence of a fire, which would continue to generate creosote. And, as with the second method, existing creosote would not be eliminated.
Compounds have been developed which can be effective in removing deposits of creosote. These generally contain chloride salts, such as sodium chloride. It is known that the effectiveness is increased in the presence of additional metallic chlorides. Unfortunately, these salts are extremely corrosive to metal, and would therefore, not be suited for the "air tight" variety of metal stoves which are in wide use today. One company has address the corrosive problem of chloride salts on metal flues. The patent to Mackowiak et al, U.S. Pat. No. 4,481,010, which is assigned to Hercules Chemical Company, Inc., attempts to overcome the corrosion problem by the addition of a corrosion inhibitor, i.e. trisodium phosphate dodecylhydrate. While the patent claims a non-corrosive product, the specifications state that the corrosive effects are "substantially reduced", as opposed to being eliminated. Furthermore, the product requires the use of a fire in its method of application.
Accordingly, there is a need for means for removing existing creosote deposits which can be applied by a single individual, and which can be applied in the absence of any fire, and which would be non-corrosive to metal.